Causes

Occurs when the origin web server refuses connections from Cloudflare. Security solutions at your origin may block legitimate connections from certain Cloudflare IP addresses. The most common ones are:

• Offline origin web server application
• Blocked Cloudflare requests

Fixes

Step 1: Contact NET Support

Contact your site administrator or NET Support to eliminate these common causes:

• Ensure your origin web server is responsive
• Review origin web server error logs to identify web server application crashes or outages.
• Confirm Cloudflare IP addresses are not blocked or rate limited
• Whitelist all Cloudflare IP ranges in your origin web server’s firewall or other security software
• Find additional troubleshooting information on the Cloudflare Community.